Electrical stimulation therapy is a fast-growing field, largely related to the successful use of implantable electrical stimulation devices for a wide range of applications. One example application is in deep brain stimulation (DBS).
Chinese patent application publication number CN 101708353 describes a brain stimulation electrode array including a number of stimulating electrodes connected through their respective individual electrode wires to an electrode interface. The electrode wires are arranged in a film being wound as a helix along the inside of a tube (FIG. 1) between a proximal and a distant end of the probe.
The film is typically coiled as a helix to suppress currents induced by MRI fields. Because of the helical shape, the foil with wires has to be much longer than the length of the probe itself, perhaps up to 1 m. Typically, a 1 m length of film is made out of loose piece straight parts of about 10-12 cm which are electrically/mechanically connected together to form a long length. At the connection points the film sections are typically overlapped, causing different mechanical/electrical properties at the overlaps.
US 2007/0123765 describe the folding of a serpentine polymer array to achieve long straight structures suitable for mounting on long carriers. Such folds or bends are, however, prone to cracking or damage, and the bend areas are thicker so that a helix coil formed in this manner will have differences in its properties along the length of the probe tube.
The inventors of the present invention have appreciated that it would be desirable to have a probe design that could do without the limitations associated with the bends and/or the connection of multiple lengths of film as above would result in a more reliable probe structure that would not have the limitations mentioned above.
Hence it is an object of the present invention to provide a medical probe device with higher mechanical/structural stability and integrity for the coiled thin film foil than in presently known solutions and in the lengths required for the interconnect of an implantable medical probe.